Metallic packing for pistons.



PAT'ENTBD DEG. 1, 190s.

fu: mams Venaus co. wlorauwo,'Msmnmwn, n c.

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ivo. 745,901.

UNTTED STATES atented December 1, 1903.

PATENT OFFICE.

METALLIC PACKING FOR PISTONS.

SPECIFICATION forming part of Letters Patent No.1745,901, dated December 1, 1903.

Application tiled March 18,1903. Serial No. 148,281. (No model.)

To @ZZ whom t may concern-.-

Be it known that we, EDWIN PEEKs, a resident of 118 Foleshill road, and FRANK BIRCH, a resident of 7 7 Widdrington road, Coventry, county of Varwick, England, subjects of the King of Great Britain, have invented certain new and useful Improvements in Metallic Packing for Pistons, of which the following is a specification.

I/Vhen metallic elastically-expansibie packing-rings are employed for packing pistons which are to be reciprocated in the cylinders of gaseous or fluid-pressure motors, pumps, or the like, means should be provided by which the said rings are held up to their work and also prevented from having motion in the direction of the axis of the piston. To this end springs or spring-actuated plungers have been located in recesses at right angles to the axis and in the body of the piston, and these springs or plungers have acted upon the interior surface of a wedge-like expansion-ring, which in its turn acts upon and between the inner edges of the packing-rings and forces the same outwardly and prevents motion in the direction of the axis of the piston. Such a construction is quite permissible in block or solid pistons; but the said constructions present very considerable disadvantages when it is required to apply such means for holding ont the packing-rings to pistons of a light trunk form, such as are employed in explosion-engines, and it is mainly to this type of pistons to which the present invention is especially applicable.

In the present invention an elastic expansion-ring divided at a part of its circumference and of larger diameter than the cylinder for which it is intended has wedge-shaped edges and is compressed before being placed in position upon the piston, so that its wedgeshaped edges come behind the wedge-shaped edges of adjacent divided spring packingrings, so that by the inherent elasticity of the expansion-ring, which seeks to regain its original diameter, the expansible packingrings are held out to the sides of the cylinder and to the top and bottom parts of the groove in the piston in which those packing-rings are located.

We will describe our invention with reference to the accompanying drawings, whereon the said'invention is shown applied, by way of example, to the piston of an explosion-motor, to which use it is eminently applicable.

Figure l shows in side elevation three of the packing-rin gs such as we employ detached from the piston, Figs. 2 and 3 being end elevations of an outer and a central ring, respectively. Fig. 4 shows in elevation a piston tted with the aforesaid rings, and Fig. 5 is a vertical central section through the piston and the improved packing-rings. Fig. 6 is a partial horizontal section of the piston to show a means for preventing the rings having a rotary movement relatively to the piston upon which they are carried.

In carrying out our invention we provide three complete rings of elastic metal. Two of such rings (marked with the reference-numerals l 2 at Fig. 1) are turned to fit the interior of the cylinder, while the third and middle ring 3 is of slightly greater external diameter, and we then make a division, such as 4., Figs. 2 and 3, in each of these rings by removinga small segment from each ring, as is shown at Figs. 1 and 2. f

At Fig. 5 the packing-rings are shown n situ, 5 being a piston such as would be employed for a petrol-motor, and it is now to be observed that the top edge of the upper ring 1 is flat and is intended to tit up against the piston or upper flange 6, while the lower edge of the same ring 1 is inclined upward from the outer circumferential surface. The lower ring 2 is oppositely formed, its upper edge being inclined downward from its outer to its inner peripheryand its lower edge is flatthat is, the plane of its lower edge is at right angles to the axis of the piston and is intended to bear upon the junk-ring or lower flange 7 of the piston 5.

The middle ring 3, which is to be located upon the piston 6 between the two'outer rings l 2, has its upper and lower edges inclined in opposite directions, so that it is of greater height upon its interior periphery than upon its exterior circular surface.

In the type of piston we have elected to describe-that is, a piston suitable for an explosion-motor-the said piston 5 is formed with an annular groove near its end to receive the aforesaidi'piston-rings, the piston-wall within the groove being less in diameter than the internal diameter of the packing-rings. The packing-rings l 2 3 are then sprung into position in this groove, being placed, as shown, so that the inclined edges of the upper and lower rings l 2 overlap and lie upon the inclined edges of the middle ring 3, while the flat edges of the upper and lower rings abut, respectively, upon the upper and lower surfaces of the groove in the piston-that is, upon the piston-flange and the junk-ring, respectively. To bringabontthis placing of the rings, itis necessary to compress the ring 3 somewhat',and the overlapping edges of the rings l 2 then bear upon the central ring 3 and maintain this placement. NVhen thus arranged, the expansive force of the middle ring 3,which has been compressed or contracted in diameter so that it shall tit within the upper and lower rings, (which were originally made ofa slightly smallerdiameter than the sprin g-ring,as aforesaid,) acts upon the opposite inclined faces of the upper and lower rings l 2, maintains the same uniformly with their circular surfaces in contact with the wall of the cylinder, while the said inclined surfaces also operate to firmly maintain the dat edges of the upper and lower rings l 2 in contact, respectively, with the piston-ring 6 and the junk-ring 7, and so prevent any possibility of motion of the metallic packing-rings l 2 3 in the direction of the axis of the piston 5 during the reciprocating motions of the latter.v

We have described the metallic packing as consisting of an upper and lower ring which forms the actual packing-rings and of a middle ring which forms what we may term a spring-ringfor maintaining the two packing-rings in their proper positions and up to their work; but we would have it understood that where found advisable we may employ more than two of these packing-rings-say three packing-rings and two spring-rings and, further, we do not limit ourselves to the form of the division of the rings.

Ve have found that our object can be efciently carried out by dividing the rings with a division parallel to the axis; but obviously the division might be made at any inclination to the axis, or it might be a zigzag division, all as found most suitable to anyparticnlarcircuinstances. Inmakingthe division in the spring-ring 3 we may cut away more of the said ring-that is, makethe division wider than the division in the packingrings l 2 proper.

In order to prevenu the rings l 2 3 revolving relatively to the piston 5, by which they are carried, we provide studs, such as 8, Fig. 6, fixed into the wall of the portion 5 and located within the groove of the piston containing the packing-rings, and such studs 8 may enter between the divided ends of the rings, as indicated at Figs. 4 and 6, or obviously the pins 8 may enter slots or grooves on the interior surfaces of the rings, and so maintain the position of the rings, or the interior surface of the rings may be tted with pins or studs engaging grooves in the piston.

As the result of the construction and combination of parts which we have now described we are enabled to produce an efficient and easily-manufactured elastic metallic packing which owing to its simplicity is not likely to get out of order, requires little or no attention in use, is not subject to movements relative to the piston which carries it during its use, and is held in perfect contact with the walls of the cylinder throughout its circular surface and without uneven pressure.

Nhat we claim as our invention, anddesire to secure by Letters Patent, is-

l. In metallic packing for pistons, the combination with a piston' having a circumferential recess in its outer surface, of two split metallic packing-rings of the same diameter as the cylinder in which the piston is employed and having their inner edges inclined inwardly, the said rings being locatedin the said recess, and a split metallic spring expansionring of slightly larger diameter than the cylinder and having its edges oppositely inclined.

2. In metallic packing for pistons, the combination with a piston having a circumferential recess in its outer surface, of two split metallic packing-rings of the same diameter as the cylinder in which the piston is employed and having their inner edges inclined inwardly, the said rings beinglocated in the said recess, a split metallic spring expansion-ring of slightly larger diameter than the cylinder and having its edges oppositely inclined, and means for preventing a revoluble movement between said piston and said packing-rings and expansion-ring.

3. In metallic packing for pistons, the combination with a piston having a circumferential recess in its outer surface, of two split metallic packing-rings of the same diameter as the cylinder in which the piston is employed and having their inner edges inclined inwardly, the said rings being located in the said recess, a split metallic spring expansion-ring of slightly largerdiameter than the cylinder and havingits edges oppositely inclined, and pins secured in the said lrecess of the piston and adapted to engage the ends of said split packing-rings and expansion-ring to prevent a revoluble movement between the same and the piston.

4. In metallic packing for pistons, the com- IOO IIO

bination With a piston having a circumferi greater exterior diameter than the interior ential recess in its outer surface, of three codiameter of said cylinder. acting split metallic packing-rings with juxtaposed tapering edges, the two outer packing-rings being of the same exterior diameter as the internal diameter of the cylinder in Witnesses:

which the piston is employed, and the cen- WALTER HEWITT,

ter or intermediate packing-ring of slightly EDMUND WRIGHT. 

